Clausena Excavata Research Articles

Seed germination and seedling emergence of the invasive exotic species, Clausena excavata

The aims of this study were to evaluate the effects of light and temperature on seed germination and the effect of light on seedling emergence of Clausena excavata, an invasive exotic species. Seeds were incubated at constant temperatures (10 to 40 ºC), under continuous white light and darkness. Seedling emergence was evaluated under full sun and canopy shade. There was no significant difference between seeds germinated in the presence or absence of light at temperatures between 20 and 35 ºC. Seeds maintained at 20 ºC germinated more slowly than other temperatures. Independent of temperature, seed germination was much more synchronised under white light than under darkness. In the field, emergence occurred in both environments, but a greater percentage was observed under full sun. Seedling emergence occurred at the same rate and synchronisation index under both conditions. C. excavata has a high invader potential in open areas and shaded environments.

Determination of a Pyranocoumarin and Three Carbazole Compounds in Clausena excavata by RP-HPLC

Clausenidin, O-methylmukonal, 3-formyl-2,7-dimethoxycarbazole, and clauszoline-J, isolated from the rhizomes and roots of Clausena excavata, exhibit anti-HIV-1 activity in a syncytial assay with EC(50) values of 5.3, 12.0, 29.1, and 34.2 microM, respectively. Due to the highly active anti-HIV-1 property, quantitative analysis of four compounds are investigated. The direct analysis of these four compounds in the crude extracts of the combined rhizomes and roots of Clausena excavata from ten various sources in Thailand by high-performance liquid chromatography is accomplished. Chromatographic separation is achieved on a C(18) column, and the mobile phase is a mixture of methanol and distilled water in a mode of isocratic or gradient elution detected at 254 nm at a flow rate of 0.6 mL/min for clausenidin, at 274 nm at a flow rate of 0.6 mL/min for O-methylmukonal, at 298 nm at a flow rate of 0.4 mL/min for 3-formyl-2,7-dimethoxycarbazole, and at 242 nm at a flow rate of 0.4 mL/min for clauszoline-J. This is the first quantitative analysis of these four anti-HIV-1 compounds from the crude extract without prior isolation and purification steps.

Constituents and Bioactivities of Clausena excavata

Clausena excavata Burm. f. (Rutaceae) is a medicinal plant which is used in folklore medicine for treatment of cold, malaria, AIDS, dermatopathy, abdominal pain, and snake-bite. This plant is a rich source of coumarins and carbazole alkaloids. So far, fifty-three coumarins and fifty-eight carbazole alokaloids were isolated from C. excavata. Furthermore, a small group of tetranortriterpenoids, steroids, flavonoids, and essential oils were also obtained from this plant. C. excavata showed diverse therapeutic activities which are antibacterial, antifungal, antiplatelet, antiplasmodial, antitumor, antinociceptive, immunomodulatory, antimycobacterial, and anti-HIV-1 activities. The incidence of HIV-1 infection leading to AIDS has increased every year, and fungal and bacterial infections, particularly TB-causing mycobacteria are prevalent in HIV-infected patients. So Clausena excavata which showed inhibition of these diseases, is very promising to be developed for treatment of AIDS.

Insecticidal activities of leaf and twig essential oils from Clausena excavata against Aedes aegypti and Aedes albopictus larvae

The current study investigates, for the first time, the mosquito larvicidal activities of leaf and twig essential oils from Clausena excavata Burm. f. and their individual constituents against Aedes aegypti L. and Aedes albopictus Skuse larvae. The yields of essential oils obtained from hydrodistillation were compared, and their constituents were determined by GC-MS analyses. The LC(50) values of leaf and twig essential oils against fourth-instar larvae of Ae. aegypti and Ae. albopictus were 37.1-40.1 microg mL(-1) and 41.1-41.2 microg mL(-1) respectively. This study demonstrated that C. excavata leaf and twig essential oils possess mosquito larvicidal activity, inhibiting the growth of mosquito larvae for both species at a low concentration. In addition, results of larvicidal assays showed that the effective constituents in leaf and twig essential oils were limonene, gamma-terpinene, terpinolene, beta-myrcene, 3-carene and p-cymene. The LC(50) values of these constituents against both mosquito larvae were below 50 microg mL(-1). Among these effective constituents, limonene had the best mosquito larvicidal activity, with LC(50) of 19.4 microg mL(-1) and 15.0 microg mL(-1) against Ae. aegypti and Ae. albopictus larvae respectively. The findings suggested that the essential oils from Clausena excavata leaf and twig and their effective constituents may be explored as a potential natural larvicide.

Anti-HBV and cytotoxic activities of pyranocoumarin derivatives

Four natural pyranocoumarins clausenidin ( 1), nordentatin ( 2), clausarin ( 3), and xanthoxyletin ( 4) were isolated from the medicinal plant Clausena excavata. Recently, we found that 1 and 2 suppressed hepatitis B virus surface antigen in HepA2 cells, and in addition, 1– 3 showed cytotoxic activity against four human cancer cell lines (A549, MCF7, KB, and KB-VIN). To explore the SAR of 1– 4, 17 pyranocoumarin analogues ( 5– 21) were designed and synthesized. Among these analogues, 5 and 10 were the most potent against hepatitis B virus with EC 50 values of 1.14 and 1.34 μM, respectively. The most interesting result in the cytotoxicity assay was the significant activity of 1, 5, and 6 against the multi-drug resistant cell line, KB-VIN, without activity against the KB cell line. These data suggest that these three compounds could be useful hits for developing MDR-inverse drugs.

A new cytotoxic carbazole alkaloid from Clausena excavata

A new carbazole alkaloid, 3-carbomethoxy-2-hydroxy-7-methoxycarbazole, Clausine-TY (1), together with two known carbazole alkaloid, Clausine-H (2) and Clausine-B (3), were isolated from the ethyl acetate extract of the stem bark of the Malaysian Clausena excavata. The structures of these compounds were elucidated by spectroscopic analyses. The new carbazole alkaloid shows significant cytotoxicity against CEM-SS cell line.

In vivo immunomodulating activity of wood extracts from Clausena excavata Burm. f.

Immunomodulating effects in Balb/C mice of aqueous extract (CEHW) and the Thai folklore preparation (CEHF) of Clausena excavata Burm. f. were investigated. Haemagglutinating antibody (HA) titers at day 0, 7, 14, 21, 28 and 35 from the serum of animals fed or injected intraperitoneally with the extracts for 5 days were compared and evaluated for humoral mediated immunity (HMI). Footpad swelling test was used to determine delayed type hypersensitivity for cell mediated immunity (CMI). CEHW and CEHF injected intraperitoneally and administered orally exhibited the same maximum antibody production of 1/800. Both extracts given orally reached the maximum antibody titer at day 7, which was 2 weeks faster than by intraperitoneal administration. However, antibody titers from CEHW injected intraperitoneally diminished without retaining whereas the CEHF retained for 1 week. Moreover, CEHW gave CMI response more than the CEHF. This study suggested the potential in vivo immunomodulating activities of extracts from Clausena excavata supporting our previous in vitro studies.

Resistance of Island Rainforest to Invasion by Alien Plants: Influence of Microhabitat and Herbivory on Seedling Performance

Experiments have promise in determining mechanisms by which communities resist invasion. Growth and survivorship of transplanted seedlings of introduced tree species (Leucaena leucocephala, Muntingia calabura, Adenanthera pavonia, and Clausena excavata) were used to assess abiotic (light regime) and biotic resistance (herbivory) to invasion of rainforest on Christmas Island (Indian Ocean). At four sites, seedlings were transplanted into the forest edge along roadside verges and into adjacent intact forest; half were caged to prevent access by the dominant seedling consumer, the red land crab (Gecarcoidea natalis). Red crab densities did not differ between roadside and forest plots. Red crabs initially reduced survivorship of Leucaena in both edge and interior plots but virtually all seedlings in the forest interior were dead after 41 weeks. Survivorship of Muntingia was also initially reduced by crabs in the forest edge, but again, all but one seedling died by the end of the experiment. Seedlings of Adenanthera and Clausena fared much better overall, surviving well in both locations. Red crabs had no overall effect on Adenanthera survival but significantly reduced survival of Clausena in forest plots. For both species, seedling performance was greater in the forest edge than in the forest interior. Red crabs had no effect on height increment for either species; however, for Clausena, red crabs reduced seedling mass in the forest interior. Both Adenanthera and Clausena were able to persist in the intact forest. Clausena is now actively invading intact rainforest, but Adenanthera appears dispersal-limited. Resistance factors in intact forest appear hierarchical: biotic resistance afforded by land crabs can impede establishment of some plant invaders but seedling responses to abiotic factors (e.g., the light regime) largely overwhelm its effect. Together, these two community attributes are likely to restrict the range of plant invaders to a small suite of species that can successfully establish in intact rainforest on the island. However, increased propagule pressure from a variety of shade-tolerant species and further declines in the abundance of the dominant seedling consumer may lead to increasing invasion success in this island rainforest.

Anti‐HIV‐1 limonoid: first isolation from Clausena excavata

A limonoid, clausenolide-1-ethyl ether (1) and two coumarins, dentatin (2) and nor-dentatin (3), were isolated from Clausena excavata. Limonoid 1 was obtained from the crude ethanol extract of the rhizomes and the roots but had not previously been isolated from C. excavata and exhibited HIV-1 inhibitory activity. Coumarins 2 and 3, with their structures related to an anti-HIV-1 substance, (+)-calanolide A (4), were obtained from the crude chloroform extract of the rhizomes. Both induced toxicity to cells used in a syncytium assay for anti-HIV-1 activity. These compounds, 1-3, did not show any cytotoxic effect against KB and BC-1 cell lines (IC(50) value > 20 microgram/mL).

Antinociceptive activity of Clausena excavata leaves

The ethanolic extract of Clausena excavata leaves, given orally at doses of 125.25 and 500 mg/kg body weight, showed significant antinociceptive activity on acetic acid induced writhing in mice.

EFFECTS OF THE HORMONAL BALANCE ON CLAUSENA EXCAVATA ANDROGENESIS

Clausena excavata, a native of Southeast Asia, displays characteristics of disease tolerance and adaptability to different kinds of soils. This species contains potential parents for the improvement of Citrus fruit rootstocks. However, it is tetraploid, unlike most Citrus and related species, which are diploid. Bringing the ploidy level back to 2n=2x would allow us to consider integrating this species into the varietal creation programme by somatic hybridisation. A diplohaploidisation programme by anther culture is currently being conducted. The effects of the hormonal balance on androgenesis and on the maturation of androgenetic embryos are described. Thirty-six hormonal combinations using benzylamino purine (BAP) and dichlorophenoxyacetic acid (2,4-D) were examined. The tendency to embryogenesis varies from 0 to 9% depending on the hormonal concentration and combination. A total of 106 plants were regenerated, of which 91 were hexaploid, 11 were tetraploid, and only two were diploid after the flow cytometry evaluation. Histological study showed that the embryos were derived not from somatic embryogenesis of the mother tissues but from microspores. (Resume d'auteur)

Heterochromatin banding patterns in Rutaceae‐Aurantioideae—a case of parallel chromosomal evolution

The heterochromatin banding patterns in the karyotypes of 17 species belonging to 15 genera of Rutaceae subfamily Aurantioideae (= Citroideae) were analyzed with the fluorochromes chromomycin (CMA) and 4'-6-diamidino-2-phenylindole-2HCl (DAPI). All species were diploids, except one tetraploid (Clausena excavata) and two hexaploids [Glycosmis parviflora agg. (aggregate) and G. pentaphylla agg.]. There are only CMA/DAPI bands, including those associated with the nucleolus. Using recent cpDNA (chloroplast DNA) sequence data as a phylogenetic background, it becomes evident that generally more basal genera with rather plesiomorphic traits in their morphology, anatomy, and phytochemistry exhibit very small amounts of heterochromatin (e.g., Glycosmis, Severinia, Swinglea), whereas relatively advanced genera from different clades with more apomorphic characters display numerous large CMA bands (e.g., Merrillia, Feroniella, Fortunella). Heterochromatin increase (from 0.7 to 13.7%) is interpreted as apomorphic. The bands are mostly located in the larger chromosomes and at telomeric regions of larger arms. However, one of the largest chromosome pair has been conserved throughout the subfamily with only very little heterochromatin. The heterochromatin-rich patterns observed in different clades of Aurantioideae appear quite similar, suggesting a kind of parallel chromosomal evolution. In respect to the current classification of the subfamily, it is proposed to divide Murraya s.l. (sensu lato) into Bergera and Murraya s.s. (sensu stricto) and to place the former near Clausena into Clauseneae s.s. and the latter together with Merrillia into Citreae s.l. The subtribes recognized within Clauseneae s.s. and Citreae s.l. appear heterogeneous and should be abandoned. On the other hand, the monophyletic nature of the core group of Citrinae, i.e., the Citrus clade with Eremocitrus, Microcitrus, Clymenia, Poncirus, Fortunella, and Citrus, is well supported.

Counlarins, limonoids and an alkaloid from Clausena excavata

In addition to a known alkaloid, some limonoids and coumarins, the new coumarins excavatins A–M have been isolated from Clausena excavata. Their structures have been assigned by NMR and CD investigations.

Plant regeneration from embryogenic calli of six Citrus related genera

Somatic embryos were induced from immature seeds of eight Citrus relatives including Aegle marmelos, Atalantia ceylanica, Citropsis gabunensis, Clausena excavata, Glycosmis pentaphylla, Microcitrus australasica, Murraya paniculata and Severinia buxifolia on MT medium supplemented with 0.05 mg l−1 2,4-D, 0.05 mg l−1 BA and 400 mg l−1 malt extract. Approximately 20% of somatic embryos from six of the genera underwent callogenesis during subculture on the same medium. After at least six successive subcultures on MT medium containing 10 mg l−1 BA, calli became growth regulator independent. Somatic embryos from growth regulator independent calli were obtained with MT medium containing 5% lactose. Plantlets were regenerated from somatic embryos on MT medium containing 0.02 mg l−1 NAA, and established in soil.

ChemInform Abstract: Carbazole Alkaloids from Clausena excavata and Their Biological Activity.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Carbazole alkaloids from Clausena excavata and their biological activity

Five new carbazole alkaloids, clausines B, E, H, I and K, as well as 22 known compounds, were isolated from the stem bark of Clausena excavata. The structures were established from spectral data and chemical transformation. These compounds showed significant inhibition of rabbit platelet aggregation and caused vasocontraction. The crude methanol extract, partitioned layers and chromatographic fractions revealed the presence of promotive and inhibitive constituents, simulatenously. These results might explain the philosophy of use in Chinese medicine, in that the dose and content variation in a prescription produced different, promotive or inhibitive, effects on therapy.

Graft Compatibility ofCitruswith Plants in thesAurantioideaeand Their Susceptibility to Citrus Tristeza Virus

Wild relatives of citrus, including 22 species in 19 genera, were evaluated for susceptibility to citrus tristeza virus (CTV). They were grafted onto rootstocks of Citrus spp., graft-inoculated with a severe strain of CTV, with the exception of a seedling of Sydney hybrid (a hybrid between species of Microcitrus), which was graft-inoculated to its stem directly. All the species used were graftable to Citrus ; however, the rate of graft success varied from 27 to 100%, and growth varied markedly. Severinia buxifolia, Atalantia monophylla, A. citroides, Fortunella polyandra, Clymenia polyandra, Swinglea glutinosa, Feronia limonia, and Feroniella lucida grew as well as Citrus grafted onto Citrus. Other species grew poorly or very poorly. Fortunella polyandra, Clymenia polyandra, Microcitrus australis, Sydney hybrid, Eremocitrus glauca, Atalantia monophylla, A. citroides, Citropsis articulate, Pleiospermium sp., Hesperethusa crenulata, Swinglea glutinosa, Aeglopsis chevalieri, Clausena excavata, C. lansium, and Merrillia caloxylon were infected with CTV based on double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) using polyclonal antibodies against CTV. On the other hand, no evidence of CTV infection was found in Severinia buxifolia brachytic form, Triphasia trifolia, Aegle marmelos, Feronia limonia, Feroniella lucida, Glycosmis pentaphylla, Murraya koenigii, and M. paniculata. Two sources of Severinia buxifolia from different stocks showed different responses to CTV.

Antiplatelet effects of clausine-D isolated from Clausena excavata

Clausine-D inhibited concentration-dependently the aggregation and release of washed rabbit platelets induced by arachidonic acid and collagen, without affecting those induced by U46619, PAF and thrombin. The IC 50 values of clausine-D on arachidonic acid-and collagen-induced platelet aggregation were calculated to be 9.0±1.1 and 58.9±0.9 μM, respectively. Thromboxane B 2 and prostaglandin D 2 formation in platelets caused by arachidonic acid were also suppressed. Clausine-D inhibited increased intracellular concentration of calcium in platelets caused by arachidonic acid and collagen, and also abolished the generation of inositol monophosphate caused by arachidonic acid, but not that by collagen U46619, PAF and thrombin. In human citrated platelet-rich plasma, clausine-D inhibited the secondary phase, but not the primary phase, of aggregation induced by epinephrine and ADP. These results indicate that the antiplatelet effect of clausine-D is due to inhibition of the formation of thromboxane A 2.

Limonoids from the Stem Bark of Clausena Excavata

AbstractA new pentanortriterpenoid, 1‐O‐methylclausenolide (1) and a known limonoid, zapoterin (4) were isolated from the stem bark of Clausena excavata (Rutaceae). Their structures were elucidated by spectral analysis and chemical transformation.

Clausine-D and -F, two new 4-prenylcarbazole alkaloids from Clausena excavata.

Two new 4-prenylcarbazole alkaloids, clausine-D (1) and -F (3) were isolated from the stem bark of Clausena excavata. Their structures were elucidated by spectral methods. Both of clausine-D (1) and -F (3) showed significant antiplatelet aggregation activity.